Focusing device for cameras



April 25, 1933. J. B. HADAWAY 1,906,059

FOCUSING DEVICE FOR CAMERAS Filed Nov. 16, 1929 3 Sheets-Sheet 1 April ,5 J. B. HADAWAY 1,906,059

FOCUSING DEVICE FOR CAMERAS Filed Nov. 16, 1929 3 Sheets-Sheet 2 Inventor? April 25, 1933. J. B. HADAWAY 1,906,059

FOCUSING DEVICE FOR CAMERAS Filed Nov. 16, 1929 3 Sheets-Sheet 3 Patented Apr. 25, 1933 p UNITED STATES PATENT OFFICE JOHN B. HADAWAY, OF SWAIPSCOTT, MASSACHUSETTS FOCU SING DEVICE FOR CAMERAS Application filed November 16, 1929. Serial No. 407,769.

This invention relates to focusing devices lenses, it being practically impossible by infor cameras, and it is herein illustrated as direct methods to estimate the distance closeembodied in a motion-picture camera. ly enough to obtain sufiiciently sharp focus- In motion-picture cameras as heretofore ing of the lens requisite for the production 3 constructed, it has been common practice to of good pictures. 7

provide a plurality of photographic lenses In view of the foregoing, the object of my which may be selectively associated with the invention is to provide an improved viewphotographic aperture of the camera to profinder and lens-shifting device for cameras vide or the taking of pictures inclu ing which will make it possible to focus photo 10 fields of various sizes and at varying disgraphic lenses accurately and ra idly withtances. Sensitized film upon which the picout necessitating the removal 0 thelenses tures are taken is customarily advanced from the camera. To this end and as illlusalong a fixed plane at right angles to the optrated, I have provided a camera comprising tical axis of the photographic aperture. Una housing having therein a photographic less the photographic lens used is of very aperture, a view-finder mounted outside of 55 short focal length, focusing of the lens is the housing, and a lens mounted for movenecessary in order to produce asharp picture ment selectively into association with the upon the film, and to this end lens mountview-finder or with the photographic aperings are commonly so made that the lenses ture, the arrangement being such that the can be shifted slightly toward or away from lens can be moved selectively into alinement the film, the mountings usually bearing with the view-finder for focusing the lens graduations to indicate the distance of an or into position in alinement with the photoobject from the camera at which the lens graphic aperture for taking ictures. Prefwill be in focus for taking a picture of that era ly the lens is mounte upon a lens object. In operating well-known types of shifter or carrier in the form of a turret at motion-picture cameras, it is customary to the forward portion of the camera housing, make use of a view-finder, which forms part said turret providing a mounting for ad of the camera, in observing an object or tional lenses of different focal len be any scene and for determining the field of view one of which ma be focused by e viewwhich it is desired to cover. A lens of the finder and move into position for taking proper focal length for that field of view is pictures. By the arrangement set forth it is then selected and the lens mounting is adpossible to adjust readily the focus of any justed to focus the lens accordin to the one of the several lenses carried by the turestimated distance of the object rom the ret so that the objects in the required field of amer view'will be sharply focused upon the film Considerable difiiculty has been experiwhen the-lens is placed in position for takenced in operating cameras in the manner ingx'pictures. Thus it will be apparent that above set forth by reason of the fact that the I ave provided a simple and effective degraduations on the lens mountings may be vice for focusing lenses without removing inaccurate or difficult to read and that it is them. from the camera and one which renexceedingly difiicult for an inexperienced ders it possible accurately and rapidly to person to estimate distances accurately. The adjust a camera for taking pictures under result of this is that the photographic lens varying conditions used is frequently not adjusted to the proper Other objects of the invention and details 5 focus, and accordingly the pictures taken are of construction will be set forth in the deblurred or indistinct. This is particularly tailed description and in the claims. evidenced in those cases in which lenses of In the drawings, long focal lengths are used, such as in tele- Fig. 1 is a plan view, partly in section, of

0 hoto work, the condition being aggravated a motion-picture camera embodying my in- 5 By the decreased depths of oci of such vention;

Fi 2 is a side view of the camera, showing a lens in alinement with the view-finder; and

Fig. 3 is a front view of the camera.

As illustrated by the drawings, my invention is embodied in a motion-picture camera of the hand type. This camera comprises a metal casing or housing 6 having a front end wall 8 which is provided with an opening 10. Rearwardly of the end wall 8 are positioned a film guide plate 12 and a second plate 14 in the central portion of which, in alinement with the opening 10, is a rectangular aperture 16 forming what is commonly known as a hotographic or exposure aperture throug which light may pass to sensitized film 17 which is fed past the aperture between the plates 12 and 14. Within the housing 6 are contained filmfeeding mechanism, not shown, which may be of any suitable and well-known construction. Projecting from the end wall 8 is a flange 18 containing shutter mechanism, not shown, and having a cover plate 19 provided with a recess 20.

Laterally of the central part of the cover plate 19 of the housing 6 is carried a stud 21 forming a bearing upon which is mounted a lens shifter or carrier comprising a turret 22, best shown in Fig. 3. The turret comprises a hub 24 from which extend three arms 26 located 120 apart. The arms have at the ends thereof screw-threaded projecting flange portions 28 (Fig. 1) arranged to receive and to sup ort lenses 30, 32 and 34. These lenses are 0 a common type, having adjustable mountings (not shown in detail) including a movable collar 35 which, when turned, will move the objective 36 of the lens inwardl or outwardl as desired. The setting of the lens can e determined by graduations 37 on the collar. Preferably, such lenses are of different focal lengths as required for obtaining sharp and sufliciently large pictures of objects at different distances. The relative locations of the stud 21, flange portions 28, and aperture 16 are such that the optical axis of any one of the lenses can be brou ht into coincidence with the optical axis 0? the photographic aperture by rotating the hub 24 on the stud 21. By this construction any one of the lenses can be selectively located in association with the photographic aperture 16 in picturetaking position.

In order to exclude light from the joint between the housing and the lens, the recess 20 in the cover late 19 is shaped to receive the projecting ange portion 28 of any one of the arms 26 when the lens carried by the flange is in alinement with the aperture 16. It is to be noted that the hub 24 is rotatably and slidably mounted upon the stud 21, the turret being forced toward the plate 19 by a spring 40. In adjusting. a lens into picture-taking position the turret is asped by a knob 42 on the end of the hu 24, is pulled outwardly, and is then turned until the required lens is in alinement with the photographic aperture, whereupon when the turret is released the spring 40 will force the lens into position with the flange 28 on the lens arm mounting in position in the recess 20. To assist in guiding a selected lens into picture taking position and to lock the lens in such position, there is provided a pin 44 on the plate 19 in position to enter one or another 0 holes 46 in the turret when a lens is located in alinement with the photographic aperture.

For determining which of the lenses carried by the turret should be utilized in taking pictures, use is made of a view-finder 48 secured by brackets 50 to the housing 6 and having an eye-piece 52 and a finderlens 54 upon which are marked (dotted lines 56, Fig. 3) the limits of the fields of the corresponding lenses of various focal lengths carried by the turret. The scene or object to form the subject of the picture is observed through the view-finder and the size of the field required is noted. The nearest corresponding lens is selected, is focused by ad usting the lens in its mounting by setting the collar 35 to correspond to the estimated distance from the camera to the scene or object, and the lens is then placed in alinement with the photographic aperture.

I have provided an auxilia view-finder for use in connection with the ienses carried by the turret 22 for accurately focusing the lenses without removing them from the camera. To this end, a view-finder 58 is mounted in brackets 60 and 62 u on the side of the housing 6. This viewnder comprises a tube 64 in the forward end of which is positioned an objective 66 havin a ground-glass viewing surface 68 and hel in the tube 64 by retaining rings 70 and a fiber washer 71. Slidably mounted in the inner end of the tube 64 is an eyeiece 72 comprising a magnifying lens 74. he eyepiece 72 carries a set-screw 76 (Fig. 2) which engages with the walls of a curved slot 78 in the tube 64 so constructed that upon turnin the eye-piece the latter is moved inwar ly or outwardly of the finder-tube and can be locked in adjusted position by tightening the set-screw. This adjustment 0 the eye-piece is for the purpose of accommodating the view-finder to the eye of the observer.

It is to be noted that the optical axis of the auxiliary viewfinder 58 is parallel to that of the photographic aperture and that the viewing surface 68 of the objective lies in the plane of the film 17 as it is guided over the plate 12. Consequently, an image of an ob ect viewed through the eye-piece 72 upon the viewing surface will correspond to that ap aring on the sensitized film 17. The viewder 58 is located relativel to the stud 21 at an angle of about 30 rom the horizontal so that, when one of the lenses, for example the lens 30 Fig. 1), is in picture-takin position, ano er lens, such as lens 32 W11 be in alinement with the optical axis of the view-finder 58, a recess being provided in the bracket 62 to receive and seat the flange portion 28 of the lens-carrying arm. ThlS prevents leakage of li ht into the view-finder tube.

W en it is desired to use the camera for taking pictures of a given object, the operator sights through the viewfinder 48 and, by means of the markings 56, determines what field of view is required selects the lens which corresponds to that field by making use of the turret in the manner above described, and places the lens in alinement with the auxiliary view-finder 58. Upon sighting through the view-finder at the object, the lens can be focused by turning its collar 35 until the image of the object appears sharply upon the viewing surface 68 of the finder. The lens is then shifted into alinement with the photo ra hic aperture 16 and the camera is rem? for operation. The object which is to be otographed can then be observed either t rough the viewfinder 48 or through the auxiliary view-finder 58, in which latter case the lens which happens to be associated with the finder 58 is focused upon the object. This method of o ration is advantageous in that, by viewing the object through the auxiliary view-finder 58, its image is enlarged by the magnifying eye-piece, thus faci itatin observation of the object to be photographe It is to be noted that the auxiliary viewfinder 58 is positioned above the central rtion of the camera housing so that it oes not interfere with the windin of the motor for the film-feeding mec anism, and furthermore that the eye-piece 72 extends rearwardly of the camera housin into a position which is readily accessib e to the operator.

Having described my invention, what I claim as new and desire to secure by Letters Patent of the United States is 1. A motion-picture camera comprisin a housing in the front face of which is docated a photographic a rture a view-finder carried by the housing and located laterally thereof, and a turret rotatably mounted upon the housing and carrying a plurality of photo aphic lenses, the relatlve locations of t e view-finder, photographic aperture, and turret bein such that each of the lenses can be rotate to place the optical axis thereof in alinement with that of the view-finder in focusin the lens, or in alinement with the optica axis of the photographic aperture for, locating the lens in picture-taking position.

2. A motion-picture camera comprising a housing havin therein a photographic aperture, a turret having a plurality of spaced arms each of which is adapted to receive and support at its end a photographic lens, a bearing-on the housing upon which the turret is rotatably mounted and so positioned relatively to the aperture that lenses carried by the arms can be rotated selectively into alinement with the aperture, and a viewfinder disposed laterally of thehousing in such position relatively to the aperture and turret that one of the lenses can be placed in alinement with the aperture with a second lens located in alinement with the viewfinder.

3. A motion-picture camera comprising a housing having therein a photographic aperture, and a recess in alinement with the a erture, a lens carrier having a flange in w ich is mounted a photographic lens, and a viewfinder tube carried on the housin and having a recess in one end thereo the lens carrier being rotatably mounted on the housing for movement relativel to the aperture and view-finder tube so t at the lens can be located in alinement with the photographic aperture with said flange seated in the recess in the housing or in alinement with the axis of the view-finder tube with the flange seated in the recess in said tube.

In testimony whereof I have signed my name to this specification.

JOHN B. HADAWAY. 

